Adhesive sheet

ABSTRACT

The present invention provide an adhesive sheet for attaching to a plasticized vinyl chloride resin article such as a blood bag made of a plasticized vinyl chloride resin, and having a center-line surface roughness Ra of 1.0 μm or higher, which comprises a film substrate and a heat-sensitive adhesive layer formed on a backside surface of the film substrate, wherein the heat-sensitive adhesive layer is composed of a resin containing a crystalline polyester resin as a main component. The adhesive sheet of the present invention is excellent in adhesive property when the adhesive sheet is attached to the article made of a plasticized vinyl chloride resin. The adhesive strength of the adhesive sheet of the present invention is not decreased even after an autoclave treatment or a storage at a low temperature. At the result, the adhesive sheet of the present invention does not cause lifting or peeling and is excellent in blocking resistance.

TECHNICAL FIELD

The present invention relates to an adhesive sheet and specifically anadhesive sheet having an excellent adhesive property, which can beattached to a plasticized vinyl chloride resin article, moreparticularly a blood bag made of a plasticized vinyl chloride resin.

BACKGROUND ART

As a blood bag in which blood is put, blood bags made of a plasticizedvinyl chloride resin have widely been used to date. The blood bag isused with a label described about information of blood being attachedthereon.

After the attached label is subjected to an autoclave treatment or asteam sterilization at 120° C. for about 30 minutes, there is aninstance where plasticizers contained in a plasticized vinyl chlorideresin move into an adhesive layer to lower the adhesive property of thelabel, and lifting or peeling of the label take place. When the label ispeeled off from the blood bag, information of blood is lost, causing aserious problem. Further, even in this case, if the label is merelypeeled off, the blood bag that the label was peeled off may be scrapped,but in the case where a plurality of labels are peeled off withoutsomeone's knowledge for some reason, and the labels are wrongly attachedto one of the other blood bags again, a blood bag with wrong bloodinformation is used, resulting in a further fatal problem.

Moreover, as a label for a blood bag, there is used a label on which atrade name, volume, ingredient representation, and manufacture etc. areprinted. In this field, a bar-code management system is established, thelabel that bar-code are printed is required. As a label for a blood bag,conventionally a label of paper as a substrate has been mainly used.However, when such label is in application to a blood bag, there havebeen problems that in treatment by a centrifugal separator to separate anormal blood cell component, a blood plasma component and the othercomponent, due to lack of strength of the label substrate, the labelcannot endure a centrifugal force and is broken, cracked, or throughfriction of the printed surface against the wall surface or the bloodbag surface, information such as bar-code becomes too unclear to read bya bar-code reader. Therefore, there has increasingly desired a plasticfilm substrate being less influenced by moisture than a paper substrate,and resistant to rubbing and strong/tough. However, although a plasticfilm substrate has the superiority described above, it has defect thatlifting or peeling occurs more easily than a paper substrate in anautoclave treatment or a steam sterilization treatment and a centrifugalseparation treatment. Further, when a heat sealing label is based on aplastic film substrate of liner-less roll type, it has a defect thatblocking occurs more easily than a paper substrate.

To solve these problems, there is proposed a label for a blood bag basedon a substrate film which is a microporous plastic film with a matrixstructure surrounding pores connecting each other so that gas can flowin said blood bag and flow out through a region labeled (see JapanesePatent No. 3404573). Lifting and peeling in an autoclave treatment canbe suppressed, however, there has been a problem that it is difficult toobtain the label with excellent blocking resistance.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide, an adhesive sheetwhich has superior adhesive property when the adhesive sheet is attachedto a plasticized vinyl chloride resin article, does not decreasestrength even after an autoclave treatment or a storage at a lowtemperature, does not cause lifting or peeling and has excellentblocking resistance.

The present inventors have perfected the present invention bydiscovering, as a result of a diligent study carried out to solve theabove-described problems, that the above-described problems can besolved by forming a heat-sensitive adhesive layer composed of a resincomprising a crystalline polyester resin as a main component, on abackside surface of the film substrate.

Thus, the present invention provides an adhesive sheet for attaching toa plasticized vinyl chloride resin article, which comprises a filmsubstrate and a heat-sensitive adhesive layer formed on a backsidesurface of the film substrate, wherein the heat-sensitive adhesive layeris composed of a resin comprising a crystalline polyester resin as amain component.

The present invention provides the adhesive sheet as described above,wherein a content ratio of the crystalline polyester resin comprised inthe resin composing the heat-sensitive adhesive layer is 50 to 100percent by mass.

The present invention provides the adhesive sheet as described above,wherein the resin composing the heat-sensitive adhesive layer iscomposed of 50 to 100 percent by mass of the crystalline polyester resinand 50 to 0 percent by mass of an amorphous polyester resin.

Additionally, the present invention provides the adhesive sheet asdescribed above, wherein a melting point of the crystalline polyesterresin is 50 to 200° C.

Also, the present invention provides the adhesive sheet as describedabove, wherein a glass transition temperature of the amorphous polyesterresin is 10 to 90° C.

Further, the present invention provides the adhesive sheet as describedabove, wherein the adhesive sheet is an adhesive sheet for attaching toa plasticized vinyl chloride resin article having a center-line surfaceroughness Ra of 1.0 μm or higher.

Furthermore, the present invention provides the adhesive sheet asdescribed above, wherein the plasticized vinyl chloride resin article isan blood bag made of a plasticized vinyl chloride resin.

PREFERRED EMBODIMENTS FOR CARRYING OUT THE INVENTION

The film substrate in the present invention includes films or sheets ofplastics of polyolefin resins such as polyethylene resin andpolypropylene; polyester resins such as polybutylene terephthalate resinand polyethylene terephthalate resin; acetate resins; ABS resins;polystyrene resins; vinyl chloride resins and the like. Among them,films or sheets of vinyl chloride resins and polyester resins arepreferable.

The film substrate may be formed in either a single layer or multiplelayers having two or more layers. The film substrate can be notoriented, or can be oriented into uniaxial direction or biaxialdirection such as longitudinal direction or cross direction. Thethickness of the film substrate is not limited, but the thickness mayusually be 10 to 250 μm, and is preferably 25 to 200 μm.

The flow direction breaking strength of the film substrate is preferably10 N/15 mm to 220 N/15 mm and the cross direction breaking strength ofthe film substrate is preferably 10 N/15 mm to 220 N/15 mm. Bycontrolling the breaking strength of the film substrate in the aboverange, the breaking of the film substrate becomes more difficult.Further the breaking strength of the film substrate becomes smaller thanthe adhesive strength of the heat-sensitive adhesive layer to theplasticized vinyl chloride resin article, therefore, if the adhesivesheet is forced to be peeled off from the plasticized vinyl chlorideresin article against the adhesive strength, the film substrate isbroken before the film substrate is peeled off from the plasticizedvinyl chloride resin article. Accordingly, it becomes difficult toreplace the adhesive sheet from the plasticized vinyl chloride resinarticle for attaching to the other plasticized vinyl chloride resinarticle intentionally. The breaking strength was measured pursuant toJIS K7127.

The film substrate can be colored or colorless transparent. A printing,a character printing or the like can be provided on the surface or thebackside surface of the film substrate. Therefore, a heat-sensitiverecording layer, a layer for receiving printing image which can providea heat transfer printing, an inkjet printing, a laser printing or thelike, a layer for improving printability, an layer for adhering inkeasily or the like can be formed on the surface or the backside surfaceof the film substrate.

Also, in order to improve the adhesion strength (keying strength) of thefilm substrate to the heat-sensitive adhesive layer, a primer treatment,a corona discharge treatment, or the like can be provided on thebackside surface of the film substrate composing the heat-sensitiveadhesive layer.

In the present invention, the heat-sensitive adhesive layer is composedof a resin comprising a crystalline polyester resin as a main component.

The crystalline polyester resin has a heat of melting crystal of 5 to 50J/g in measuring by a differential scanning calorimeter. When the heatof melting crystal is low, the crystalline polyester resin becomesnearly amorphous, the resin strength becomes lower, the adhesivestrength decreases, and also, the blocking resistance is inferior. Whenthe heat of melting crystal is high, the crystallization rate becomesfaster, the open time becomes shorter, and the crystal shrinking becomeslarger, so that the adhesive strength is decreased. The heat of meltingcrystal is preferably 10 to 45 J/g, and more preferably 15 to 40 J/g.

The crystalline polyester resin has a melting point of preferably 50 to200° C., and more preferably 70 to 150° C. The crystalline polyesterresin has a glass transition temperature of preferably −30 to 70° C.,and more preferably −20 to 50° C.

The content ratio of the crystalline polyester resin comprised in theresin composing the heat-sensitive adhesive layer is preferably 50 to100 percent by mass, more preferably 60 to 100 percent by mass,furthermore preferably 70 to 100 percent by mass and most preferably 80to 100 percent by mass.

The resin composing the heat-sensitive adhesive layer can contain theother resins other than the crystalline polyester resin. The otherresins include various resins, but preferably amorphous polyesterresins.

The amorphous polyester resin has excellent wettability and excellentfollowability to the surface of the article when the adhesive sheet isattached to the plasticized vinyl chloride resin article. In particular,when the surface of the article is rough, the amorphous polyester resinhas excellent wettability and excellent followability of the adhesivesheet to the surface of the article.

The amorphous polyester resin has a glass transition temperature ofpreferably 10 to 90° C., and more preferably 30 to 80° C. When the glasstransition temperature of the amorphous polyester resin is less than 10°C., the blocking resistance trends to decrease easily. When the glasstransition temperature of the amorphous polyester resin is more than 90°C., it takes long time to melt, and therefore, there is an instance thatthe heat sealing property becomes worse.

The content ratio of the amorphous polyester resin comprised in theresin composing the heat-sensitive adhesive layer is preferably 50 to 0percent by mass, more preferably 40 to 0 percent by mass, furthermorepreferably 30 to 0 percent by mass and most preferably 20 to 0 percentby mass. When the amorphous polyester resin is comprised in the resincomposing the heat-sensitive adhesive layer, the lower limit value ofthe content is preferably not less than 0.1 percent by mass, morepreferably not less than 0.5 percent by mass, and most preferably notless than 1 percent by mass.

The polyester resin as described above can be produced by usuallypolymerizing a polyol and a polyhydric carboxylic acid.

The polyol includes diethylene glycol, dipropylene glycol, polyetherpolyols such as triethylene glycol and polyethylene glycol, polyesterpolyols, ethylene glycol, propylene glycol, 1, 4-butanediol, 1,3-pentanediol, neopentyl glycol, 1, 6-hexanediol, cyclohexanediol, 2, 2,4-trimethyl-1,3-pentanediol, glycerol, glycerol monoallyl ether,trimethylol ethane, trimethylol propane, and pentaerythritol. The polyolcan be utilized singly or in combination of 2 or more members.

The polyhydric carboxylic acid includes malonic acid, phthalic acid,terephthalic acid, isophthalic acid, tetrahydro phathalic acid, methyltetrahydro phthalic acid, hexahydro phthalic acid, methyl hexahydrophthalic acid, succinic acid, glutaric acid, hexachloro endomethylenetetrahydrophthalic acid, endomethylene tetrahydrophthalic acid,endomethylene hexahydrophthalic acid, adipic acid, sebasic acid, azelaicacid, dimmer acid, decadicarboxylic acid, cycrohexane-dicarboxylic acid,trimellitic acid, pyromellitic acid, trimesic acid, and cycropentanedicarboxylic acid. The polyhydric carboxylic acid can be utilized singlyor in combination of 2 or more members.

The combination of the polyol and the polyhydric carboxylic acid can beproperly selected to produce the crystalline polyester resin or theamorphous polyester resins and to control the glass transitiontemperature to be in the range described above.

The polyester resin can be utilized singly or in combination of 2 ormore members.

The heat sensitive adhesive layer is preferably cured by adding acrosslinking agent. By crosslinking the crosslinking agent, the heatsensitive adhesive layer can have strong adhesive strength, strongcohesive force and more excellent blocking resistance. The crosslinkingagent includes polyisocyanate compounds, epoxy compounds, aluminiumchelate compounds and ethylene imine compounds. Preferable crosslinkingagent is polyisocyanate compounds. Most preferable crosslinking agentincludes aliphatic or alicyclic polyisocyanate compounds in view of theweather resistance. The polyisocyanate compounds include polyisocyanatecompounds having two or more isocyanate groups per one molecule, and,for example, various polyisocyanate compounds such as di-isocyanatecompounds, tri-isocyanate compounds, tetra-isocyanate compounds,penta-isocyanate compounds and hexa-isocyanate compounds.

Examples of the polyisocyanate compounds include aromaticpolyisocyanates such as tolylene diisocyanate, xylylene di-isocyanate,diphenylmethane di-isocyanate, biphenyl di-isocyanate,3,3′-dimethyl-4,4′-biphenylene di-isocyanate,methylene-bis(phenylisocyanate), isophorone di-isocyanate, and alicyclicpolyisocyantes such as hydrogenated tolylene diisocyanate, hydrogenatedxylylene di-isocyanate and hydrogenated diphenylmethane di-isocyanate,and aliphatic polyisocyanates such as 1,4-tetra-methylene di-isocyanate,hexamethylene diisocyanate and 2,2,4-trimethylhexamethylenediisocyanate.

When crosslinking agent is used, a crosslinking promoting agent ispreferably added.

The crosslinking promoting agent includes, for example, amine compoundssuch as triethylamine and tetramethylbutanediamine, and metal compoundssuch as stannous chloride, dimethyl dichloro tin, trimethyl tinhydroxide, di-n-butyl tin dilaurate, dibutyl tin diacetate, dibutyl tinsulfide, ferric chloride, ferric acetylacetate, cobalt naphthenate,bismuth nitrate, lead oleate and amtimony trichloride.

When the crosslinking agent is used, the used polyester resin haspreferably a hydroxyl value of 1 or more mgKOH/g. The upper limit of thehydroxyl value of the polyester resin can be selected properly and ispreferably not more than 50 mgKOH/g, and more preferably not more than20 mgKOH/g. The most preferable range of the hydroxyl value of thepolyester resin is 2 to 10 mgKOH/g. Among the polyester resins, thecrystalline polyester resin has most preferably the hydroxyl value ofthe range described above.

The adding amount of the crosslinking agente is preferably 0.01 to 10parts by mass, and more preferably 0.1 to 5 parts by mass to 100 partsby mass of the polyester resin.

Additionally, one or more additives can be contained in theheat-sensitive adhesive layer, according to needs. The additives includefillers, dyes, pigments, antioxidants and ultraviolet absorbers. Thefillers include inorganic fillers such as titanium dioxide, silica,calcium carbonate, barium sulfate and talc, and organic fillers such asstarch. The antioxidants include anilide antioxidants, phenolantioxidants, phosphite antioxidants, and thioester antioxidants. Theultraviolet absorbers include benzophenone ultraviolet absorbers andbenzotriazole ultraviolet absorbers.

The heat-sensitive adhesive layer can be formed by applying aheat-sensitive adhesive on the backside surface of the film substrate,which is a mixture prepared by mixing the components described above,and optionally mixing a diluent additionally to control a properviscosity, and optionally drying and/or crosslinking, or can be formedby applying the heat-sensitive adhesive on a surface of a release base,optionally drying and/or crosslinking, and then laminating the backsidesurface of the film substrate on the surface of the applied layer.

The diluents contained in the heat-sensitive adhesive or added later,include aromatic hydrocarbons such as benzene, toluene and xylene;aliphatic hydrocarbons such as hexane, heptane, octane, nonane anddecane; ketones such as methyl ethyl ketone, diethyl ketone anddiisopropyl ketone. The formulating amount of the diluent can beselected properly to control the demanded viscosity.

The thickness of the heat-sensitive adhesive layer is not limitedparticularly, but usually 5 to 40 μm, and preferably 10 to 25 μm.

In the present invention, a printing or a character printing can beprovided on the surface of the heat-sensitive adhesive layer.

And, the surface of the heat-sensitive adhesive layer can be coveredwith a release liner.

The release liner is made of a support base having release property onat least one surface. The support base can have the surface havingrelease property obtained by applying a release agent, or the surfacewithout applying a release agent.

The support base of the release liner includes, for example, papers,synthetic papers and plastic films. The papers include, for example,glassine paper and polyethylene laminated paper. The plastic filmsinclude, for example, films of plastics such as polyolefine resin ofpolyethylene resin, polypropylene resin or the like, polyester resin ofpolybutylene terephthalate resin, polyethylene terephthalate resin orthe like, acetate resin, polystyrene resin and vinyl chloride resin. Theproper examples of the release liner having the surface without applyinga release agent, include polyolefin resin film such as polyethyleneresin film, polypropylene resin film and the like, and films obtained bylaminating the polyolefin resin film on the paper or the other films.

The thickness of the support base of the release liner is not limitedparticularly, and the thickness is generally 15 to 300 μm.

The release agent used in the release liner includes a silicone-basedresin, an alkyd resin, a fluorine-based resin and a long-chain alkylbased resin.

The thickness of the adhesive sheet laminated with the film substrate,the heat-sensitive adhesive layer and the release liner, is preferably athickness which can introduce into a printer or the like, and generallya level of about 50 to 300 μm.

The adhesive sheet of the present invention can be a flat sheet, or asheet wound in a roll shape.

The adhesive sheet of the present invention can be used in various usesfor attaching the heat-sensitive adhesive layer. The adhesive sheet isuseful particularly when an adherend is an article made of a plasticizedvinyl chloride resin. The adhesive sheet of the present invention doesnot cause lifting or peeling, even if a sterilization treatment isconducted after attaching to a blood bag made of a plasticized vinylchloride resin. Therefore, the adhesive sheet of the present inventionis particularly useful in the use as an indication label or a managementlabel of the blood bag. The adhesive sheet of the present invention canparticularly operate effectively when the adherend made of theplasticized vinyl chloride resin has a rough surface. The center-linesurface roughness of the adherend made of the plasticized vinyl chlorideresin is preferably 1 μm or more, and more preferably 1.5 μm or more.

The center-line surface roughness of the adherend made of theplasticized vinyl chloride resin is not limited particularly, but it ispreferably not more than 20 μm, and more preferably not more than 10 μm.

The adhesive sheet for attaching to the blood bag is printed on thesurface of the film substrate with the information such as a blood typeand collecting date and time of blood. The attaching of the adhesivesheet to the blood bag is conducted before charging the blood into theblood bag.

The attaching of the adhesive sheet to the adherend, is generallyconducted by superimposing the heat-sensitive adhesive layer directly onthe surface of the adherend and then heating and pressing. The heatingtemperature is preferably 80 to 160° C. in general, more preferably 100to 150° C. and most preferably 120 to 140° C. The pressure for thepressing is generally 0.5 to 10 kg/cm². The time for the pressing ispreferably 0.1 to 5 seconds and more preferably 0.5 to 3 seconds.

The adhesive sheet of the present invention does not decrease in thestrength even after an autoclave treatment or a storage at a lowtemperature, does not cause lifting or peeling, has excellent adhesiveproperty for the long time, and is excellent in blocking resistance. Theadhesive sheet of the present invention is extremely excellent inpracticability.

EXAMPLES

In the following, the present invention is explained in more detail byExamples. Further, the present invention is not limited at all by theseExamples.

The adhesive strength measuring test in the Examples was conductedaccording to the following methods.

(1) Adhesive Strength Measuring Test

On the surface having a center-line surface roughness Ra of 6.3 μm of ablood bag made of a plasticized vinyl chloride resin, a surface of aheat-sensitive adhesive layer of an adhesive sheet was attached by heatsealing at a temperature of 130° C. for a pressing time of 2 secondsunder a pressure of 3 kg/cm³ with a heat sealer (manufactured by TESTERSANGYO Co. LTD., trade name “HEAT SEAL TESTER TP-701”). The adhesivesheets attached to the blood bag were respectively peeled off at a pullspeed of 300 mm/min by a 180° peeling method, at a condition after 30minutes from the heat sealing (Condition 1) and at a condition afterautoclave treatment for 40 minutes with a high pressure sterilizationmachine (manufactured by HIRAYAMA MANUFACTURING CORPORATION, trade name“AUTO HIGH PRESSURE STERILIZATION MACHINE HA-24 TYPE”) after 30 minutesfrom the heat sealing (Condition 2). The peeled states of the adhesivesheet and the blood bag in condition 1 or condition 2 were observed byvisual. The peeled states were evaluated on the basis of the followingstandards.

⊚: The blood bag made of plasticized vinyl chloride resin or the filmsubstrate of the adhesive sheet was broken.◯: A part of the blood bag made of plasticized vinyl chloride resin or apart of the film substrate of the adhesive sheet was broken.X: The blood bag made of plasticized vinyl chloride resin or the filmsubstrate of the adhesive sheet was not broken, and the adhesive sheetwas peeled off.

(2) Autoclave Applicability

On the surface having a center-line surface roughness Ra of 6.3 μm of ablood bag made of a plasticized vinyl chloride resin, a surface of aheat-sensitive adhesive layer of an adhesive sheet was attached by heatsealing at a temperature of 130° C. for a pressing time of 2 secondsunder a pressure of 3 kg/cm³ with a heat sealer (manufactured by TESTERSANGYO Co. LTD., trade name “HEAT SEAL TESTER TP-701”). After 30 minutesfrom the heat sealing, an autoclave treatment was conducted for 40minutes with a high pressure sterilization treatment machine(manufactured by HIRAYAMA MANUFACTURING CORPORATION, trade name “AUTOHIGH PRESSURE STERILIZATION MACHINE”). Lifting or peeling of theadhesive sheet was observed by visual. The results were evaluated on thebasis of the following standards.

◯: Lifting or peeling was not caused in the adhesive sheet.X: Lifting or peeling was caused in the adhesive sheet.

(3) Blocking Test

The heat-sensitive adhesive layer of the adhesive sheet was superposedon the backside surface of the heat-sensitive adhesive layer of theadhesive sheet. The superposed adhesive sheet was left for 120 hours inthe environment of 60° C. with application of a load of 20 g/cm². Andthen, the backside surface of the adhesive sheet was observed by visualwhether there is blocking or not. The results were evaluated on thebasis of the following standards.

⊚: The adhesive sheet was peeled off without resistance.◯: The adhesive sheet was peeled off with making some noise.Δ: The heat sealing agent or a part of the film substrate was left onthe backside surface of the heat-sensitive adhesive layer of theadhesive sheet.X : The film substrate was broken.

Example 1

A solution obtained by mixing 100 parts by mass (as solid component) ofa crystalline polyester resin having a glass transition temperature of10° C. and a melting point of 110° C. (manufactured by Nippon SyntheticChemical Industry Co. Ltd., trade name “POLYESTAR SP-180 S20TM”, a heatof melting crystal of 26.99 J/g measured by a differential scanningcalorimeter) and 100 parts by mass of a diluent which is toluene, wasapplied on a backside surface (non-treatment surface) of a filmsubstrate composed of a polyester film sheet having a layer for adheringink easily on the surface (produced by TOYOBO CO., LTD., trade name“CRISPER K2311” , a thickness of 50 μm, flow direction breaking strengthof 94 N/15 mm, cross direction breaking strength of 118 N/15 mm) in anamount to form a heat-sensitive adhesive layer having a dried thicknessof 12 μm and dried. And then, on the surface of the formedheat-sensitive adhesive layer, a release liner composed of apolyethylene terephthalate film having a silicone resin layer on onesurface (manufactured by LINTEC Corporation, trade name “SP-PET38CL”, athickness of 38 μm) was laminated to make an adhesive sheet.

On the surface of the film substrate of the adhesive sheet, bloodinformation was printed. Next, the printed adhesive sheet was cut in alabel size and then the release liner was peeled off. The obtainedadhesive sheet was heat sealed at a temperature of 130° C. for apressing time of 2 seconds under a pressure of 3 kg/cm³ on the surfacehaving a center-line surface roughness Ra of 6.3 μm of a blood bag madeof a plasticized vinyl chloride resin to attach. When the adhesive sheetwas attached, peeling or slipping was not observed.

After the adhesive sheet was left for 3 months in the state, theadhesive condition of the adhesive sheet was observed by visual. Liftingor peeling was not observed. The adhesive strength measuring test, theautoclave applicability and the blocking test were conducted. Theresults are shown in Table 1.

Example 2

An adhesive sheet was prepared in the same manner as Example 1 exceptthat a solution obtained by mixing 100 parts by mass (as solidcomponent) of a crystalline polyester resin having a glass transitiontemperature of 10° C. and a melting point of 110° C. (manufactured byNippon Synthetic Chemical Industry Co. Ltd., trade name “POLYESTARSP-180 S20TM”) and 100 parts by mass of a diluent which is toluene, wasapplied on a backside surface (non-treatment surface) of the filmsubstrate and was dried to form a heat-sensitive adhesive layer.

The obtained adhesive sheet was heat sealed at a temperature of 130° C.for a pressing time of 2 seconds under a pressure of 3 kg/cm³ on thesurface having a center-line surface roughness Ra of 2 μm of a blood bagmade of a plasticized vinyl chloride resin to attach. When the adhesivesheet was attached, peeling or moving was not observed.

After the adhesive sheet was left for 3 months in the state, theadhesive condition of the adhesive sheet was observed by visual. Liftingor peeling was not observed. The adhesive strength measuring test, theautoclave applicability and the blocking test were conducted. Theresults are shown in Table 1.

Example 3

An adhesive sheet was prepared in the same manner as Example 1 exceptthat a solution obtained by mixing 90 parts by mass (as solid component)of a crystalline polyester resin having a glass transition temperatureof 10° C. and a melting point of 110° C. (manufactured by NipponSynthetic Chemical Industry Co. Ltd., trade name “POLYESTAR SP-180S20TM”), 10 parts by mass (as solid component) of an amorphous polyesterresin having a glass transition temperature of 65° C. (manufactured byNippon Synthetic Chemical Industry Co. Ltd., trade name “POLYESTARTP-235 S20TM”) and 100 parts by mass of a diluent which is toluene, wasapplied on a backside surface (non-treatment surface) of the filmsubstrate and was dried to form a heat-sensitive adhesive layer.

The obtained adhesive sheet was heat sealed at a temperature of 130° C.for a pressing time of 2 seconds under a pressure of 3 kg/cm³ on thesurface having a center-line surface roughness Ra of 2 μm of a blood bagmade of a plasticized vinyl chloride resin to attach. When the adhesivesheet was attached, peeling or moving was not observed.

After the adhesive sheet was left for 3 months in the state, theadhesive condition of the adhesive sheet was observed by visual. Liftingor peeling was not observed. The adhesive strength measuring test, theautoclave applicability and the blocking test were conducted. Theresults are shown in Table 1.

Example 4

An adhesive sheet was prepared in the same manner as Example 1 exceptthat a solution obtained by mixing 60 parts by mass (as solid component)of a crystalline polyester resin having a glass transition temperatureof 10° C. and a melting point of 110° C. (manufactured by NipponSynthetic Chemical Industry Co. Ltd., trade name “POLYESTAR SP-180S20TM”), 40 parts by mass (as solid component) of an amorphous polyesterresin having a glass transition temperature of 65° C. (manufactured byNippon Synthetic Chemical Industry Co. Ltd., trade name “POLYESTARTP-235 S20TM”) and 100 parts by mass of a diluent which is toluene, wasapplied on a backside surface (non-treatment surface) of the filmsubstrate and was dried to form a heat-sensitive adhesive layer.

The obtained adhesive sheet was heat sealed at a temperature of 130° C.for a pressing time of 2 seconds under a pressure of 3 kg/cm³ on thesurface having a center-line surface roughness Ra of 2 μm of a blood bagmade of a plasticized vinyl chloride resin to attach. When the adhesivesheet was attached, peeling or moving was not observed.

After the adhesive sheet was left for 3 months in the state, theadhesive condition of the adhesive sheet was observed by visual. Liftingor peeling was not observed. The adhesive strength measuring test, theautoclave applicability and the blocking test were conducted. Theresults are shown in Table 1.

Example 5

An adhesive sheet was prepared in the same manner as Example 1 exceptthat a solution obtained by mixing 90 parts by mass (as solid component)of a crystalline polyester resin having a glass transition temperatureof 10° C. and a melting point of 110° C. (manufactured by NipponSynthetic Chemical Industry Co. Ltd., trade name “POLYESTAR SP-180S20TM”), 10 parts by mass (as solid component) of an amorphous polyesterresin having a glass transition temperature of 40° C. (manufactured byNippon Synthetic Chemical Industry Co. Ltd., trade name “POLYESTARTP-219 S30TO”) and 100 parts by mass of a diluent which is toluene, wasapplied on a backside surface (non-treatment surface) of the filmsubstrate and was dried to form a heat-sensitive adhesive layer.

The obtained adhesive sheet was heat sealed at a temperature of 130° C.for a pressing time of 2 seconds under a pressure of 3 kg/cm³ on thesurface having a center-line surface roughness Ra of 2 μm of a blood bagmade of a plasticized vinyl chloride resin to attach. When the adhesivesheet was attached, peeling or moving was not observed.

After the adhesive sheet was left for 3 months in the state, theadhesive condition of the adhesive sheet was observed by visual. Liftingor peeling was not observed. The adhesive strength measuring test, theautoclave applicability and the blocking test were conducted. Theresults are shown in Table 1.

Example 6

An adhesive sheet was prepared in the same manner as Example 1 exceptthat a solution obtained by mixing 100 parts by mass (as solidcomponent) of a crystalline polyester resin having a glass transitiontemperature of 10° C. and a melting point of 110° C. (manufactured byNippon Synthetic Chemical Industry Co. Ltd., trade name “POLYESTARSP-180 S20TM”, a hydroxyl value of 8 mgKOH/g), 0.5 parts by mass (assolid component) of a crosslinking agent (aromatic polyisocyanatecompound, manufactured by TOYO INK MFG. Co. Ltd., trade name “BHS8515”)and 100 parts by mass of a diluent which is toluene, was applied on abackside surface (non-treatment surface) of the film substrate and wasdried to form a heat-sensitive adhesive layer.

The obtained adhesive sheet was heat sealed at a temperature of 130° C.for a pressing time of 2 seconds under a pressure of 3 kg/cm³ on thesurface having a center-line surface roughness Ra of 2 μm of a blood bagmade of a plasticized vinyl chloride resin to attach. When the adhesivesheet was attached, peeling or moving was not observed.

After the adhesive sheet was left for 3 months in the state, theadhesive condition of the adhesive sheet was observed by visual. Liftingor peeling was not observed. The adhesive strength measuring test, theautoclave applicability and the blocking test were conducted. Theresults are shown in Table 1.

Comparative Example 1

An adhesive sheet was prepared in the same manner as Example 1 exceptthat an ethylene-vinyl acetate copolymer resin (manufactured byTOYO-MORTON Co. Ltd., trade name “AD-1790-15”) was used instead of acrystalline polyester resin having a glass transition temperature of 10°C. and a melting point of 110° C.

The obtained adhesive sheet was attached on the surface having acenter-line surface roughness Ra of 6.3 μm of a blood bag made of aplasticized vinyl chloride resin in the same manner as Example 1.

The adhesive strength measuring test, the autoclave applicability andthe blocking test were conducted. The results are shown in Table 1.

Comparative Example 2

An adhesive sheet was prepared in the same manner as Example 1 exceptthat an amorphous polyester resin having a glass transition temperatureof 65° C. (manufactured by Nippon Synthetic Chemical Industry Co. Ltd.,trade name “POLYESTAR TP-235 S20TM”) was used instead of a crystallinepolyester resin having a glass transition temperature of 10° C. and amelting point of 110° C.

The obtained adhesive sheet was attached on the surface having acenter-line surface roughness Ra of 6.3 μm of a blood bag made of aplasticized vinyl chloride resin in the same manner as Example 1.

The adhesive strength measuring test, the autoclave applicability andthe blocking test were conducted. The results are shown in Table 1.

Comparative Example 3

An adhesive sheet was prepared in the same manner as Example 1 exceptthat an amorphous polyester resin having a glass transition temperatureof 65° C. (manufactured by Nippon Synthetic Chemical Industry Co. Ltd.,trade name “POLYESTAR TP-235 S20TM”) was used instead of a crystallinepolyester resin having a glass transition temperature of 10° C. and amelting point of 110° C.

The obtained adhesive sheet was attached on the surface having acenter-line surface roughness Ra of 2 μm of a blood bag made of aplasticized vinyl chloride resin in the same manner as Example 1.

The adhesive strength measuring test, the autoclave applicability andthe blocking test were conducted. The results are shown in Table 1.

Comparative Example 4

An adhesive sheet was prepared in the same manner as Example 1 exceptthat an amorphous polyester resin having a glass transition temperatureof 65° C. (manufactured by Nippon Synthetic Chemical Industry Co. Ltd.,trade name “POLYESTAR TP-235 S20TM”) was used instead of a crystallinepolyester resin having a glass transition temperature of 10° C. and amelting point of 110° C.

The obtained adhesive sheet was attached on the surface having acenter-line surface roughness Ra of 0.8 μm of a blood bag made of aplasticized vinyl chloride resin in the same manner as Example 1.

The adhesive strength measuring test, the autoclave applicability andthe blocking test were conducted. The results are shown in Table 1.

Comparative Example 5

An adhesive sheet was prepared in the same manner as Example 1 exceptthat a solution obtained by mixing 10 parts by mass (as solid component)of a crystalline polyester resin having a glass transition temperatureof 10° C. and a melting point of 110° C. (manufactured by NipponSynthetic Chemical Industry Co. Ltd., trade name “POLYESTAR SP-180S20TM”), 90 parts by mass (as solid component) of an amorphous polyesterresin having a glass transition temperature of 65° C. (manufactured byNippon Synthetic Chemical Industry Co. Ltd., trade name “POLYESTARTP-235 S20TM”) and 100 parts by mass of a diluent which is toluene, wasapplied on a backside surface (non-treatment surface) of the filmsubstrate and was dried to form a heat-sensitive adhesive layer.

The obtained adhesive sheet was attached on the surface having acenter-line surface roughness Ra of 6.3 μm of a blood bag made of aplasticized vinyl chloride resin in the same manner as Example 1.

The adhesive strength measuring test, the autoclave applicability andthe blocking test were conducted. The results are shown in Table 1.

TABLE 1 Adhesive property Condition Condition Autoclrave Blocking 1 2applicability test Example 1 ⊚ ⊚ ◯ ◯ Example 2 ⊚ ⊚ ◯ ◯ Example 3 ⊚ ⊚ ◯ ◯Example 4 ⊚ ◯ ◯ ◯ Example 5 ⊚ ⊚ ◯ ◯ Example 6 ⊚ ⊚ ◯ ⊚ Comparative X X X◯ Example 1 Comparative ◯ X X X Example 2 Comparative ◯ X X X Example 3Comparative ◯ ◯ ◯ X Example 4 Comparative ◯ ◯ ◯ Δ Example 5

1. An adhesive sheet for attaching to a plasticized vinyl chloride resinarticle, which comprises a film substrate and a heat-sensitive adhesivelayer formed on a backside surface of the film substrate, wherein theheat-sensitive adhesive layer is composed of a resin comprising acrystalline polyester resin as a main component.
 2. The adhesive sheetas claimed in claim 1, wherein a content ratio of the crystallinepolyester resin comprised in the resin composing the heat-sensitiveadhesive layer is 50 to 100 percent by mass.
 3. The adhesive sheet asclaimed in claim 1, wherein the resin composing the heat-sensitiveadhesive layer is composed of 50 to 100 percent by mass of thecrystalline polyester resin and 50 to 0 percent by mass of an amorphouspolyester resin.
 4. The adhesive sheet as claimed in claim 1, wherein amelting point of the crystalline polyester resin is 50 to 200° C.
 5. Theadhesive sheet as claimed in claim 3, wherein a glass transitiontemperature of the amorphous polyester resin is 10 to 90° C.
 6. Theadhesive sheet as claimed in claim 1, wherein the adhesive sheet is anadhesive sheet for attaching to a plasticized vinyl chloride resinarticle having a center-line surface roughness Ra of 1.0 μm or higher.7. The adhesive sheet as claimed in claim 6, wherein the plasticizedvinyl chloride resin article is a blood bag made of a plasticized vinylchloride resin.